Mechanism and Application of Lifting Drill Cuttings with a Low Specific Gravity Drilling Fluid.

For a long time, the bentonitic drilling mud or the mud based on bentonite and other substances has been used widely.These types of mud have such characteristics as high specific gravity and high viscosity.Bentonite, the main component of the ordinary type of mud, is heavy, so it is hard to transport or to use in the field.A new type of drilling fluid powder have been developed to solve these problems.It is made of polymer which expands enormously when it absorbs water.The powder and water are required to make drilling fluid.Its concentration is about 0.3-0.6%inweight.The specific gravity of this drilling fiuid is close to that of water.But the ability of this new type of drilling fluid is as same as that of ordinary drilling mud.Moreover, thisnew type of drilling fluid has some superior characteristics.The mechanism of lifting drill cuttings with this new type of drilling fluid and some examples of its application are presented in this paper.1.